MEIC R&D

1. MEIC R&D Yuhong Zhang

2. Outline • MEIC R&D Issues • View 1: EIC AC Recommendations • View 2: MEIC Design Status • View 3: Accelerator Technology Challenges • Present Plan • CASA/JLab Internal Resources • External Collaborations • Research Proposals • Proposed Research Focuses • Path Forward and Open Questions

3. EIC Advisory Committee Recommendations • Highest priority • Design of JLab EIC • High current (e.g., 50 mA) polarized electron gun • Demonstration of high energy-high current recirculation ERL • Beam-beam simulations for EIC • Polarized 3He production and acceleration • Coherent electron cooling • High priority, but could wait until decision made • Compact loop magnets • Electron cooling for JLab concepts • Traveling focusing scheme (it is not clear what the loss in performance would be if it doesn’t work; it is not a show stopper if it doesn’t) • Development of eRHIC-type SRF cavities • Medium priority • Crab cavities • ERL technology development at JLab Most critical Only for very low ion energy, 12 GeV or less

4. MEIC Machine Design Status • Short term design goal (by next EIC AC meeting, 12/2010) • We are committed to completing a MEIC design with sufficient technical details • Short term technical Strategy • Limiting as many MEIC design parameters as we can within or close to the present state-of-art in order to minimize technical uncertainty and required R&D • Mid-term design goal (by next NSAC Long Range Plan, ~2013) • A complete design supported with solid R&Ds & a zero-th order design report • Unfinished design tasks (under the short term goal) • Electron complex • RF system • Polarization lifetime by spin tracking • Instability (feedback for multi-bunches) • Ion complex • Polarized and un-polarized ion sources • SRF Linac & pre-booster (cooling, tracking) • Design of big boosters • RF system in boosters and collider ring • Ion polarization (scheme, tracking) • Electron cooling (cooler design, simulations) • Instabilities, electron cloud • Interaction region • IR design, magnet, background • Tracking studies and dynamics aperture • Crab crossing and cavities • Beam-beam simulations

5. Accelerator Technology Challenges • Interaction region design and limits with chromatic compensation • Electron cooling • Crab crossing and crab cavity • Forming high intensity low energy ion beam • Beam-beam effect • Depolarization (including beam-beam) and spin tracking • Traveling focusing for very low energy ion beam

6. Three Most Outstanding R&D Issues • Electron cooling of medium energy ions • Effectiveness/efficiency of electron cooling at medium ion energy • Design of circulator cooler ring, development of fast kicker • High average beam current (ampere class) ERL • Dynamics of electron beam in a circulator ring & long term space charge effect • Dynamics of two coupled beams (cooling electrons and ions) • Formation of high average current ion beams with high bunch repetition rate, small emittance and short bunch • Negative (H-, D-) ion sources and strip injections • Ion SRF linac • Low energy (~100 keV) long bunch (DC) electron cooling • Space charge effect in pre-booster • Ion polarization in a Figure-8 ring • Demonstrate advantage of a Figure-8 ring for ion beams • Polarized deuteron beam

7. JLab MEIC Accelerator Design Team • CASA (core team members) • Alex Bogacz, PavelChevtsov (leaving), SlavaDerbenev, Geoff Krafft, Rui Li, VasiliyMorozov, Balsa Terzic, ByungYunn, Yuhong Zhang one graduate student (HishamSayed) • Approximately 4.35 FTE • Expertise: mostly theoretical/computational, some operational (on linac & ERL) linear optics, recirculatedlinac, ERL, instability, collective effects polarization theory, electron cooling theory, beam-beam simulations • New postdoc/staffs: up to 2 to 3 in the near future (pending grant applications) • Within JLab • RF system: Frank Marhauser, Bob Rimmer, Haipeng Wang • Polarized electron source and photo-injector: Matt Poelker • Expertise critically needed • Proton/ion beams, ion source and linac, storage ring, ring-ring collider • Situation changed significantly after arriving of two ion beam/collider experts: FulviaFilat and Todd Satogata

8. External Collaborations • IR/detector design M. Sullivan (SLAC) • Ion sources V. Dudnikov, R. Johnson (Muons, Inc) V. Danilov (ORNL) • SRF Linac/Pre-booster S. Manikonda, P. Ostroumov* (ANL) B. Erdelyi (NIU) • Beam-beam simulation J. Qiang (LBNL) (supported by SciDAC) • Electron cooling simulation D. Bruhwiler (Tech X) (supported by SciDAC) • Polarization A. Kondratenko (Novosibirsk) • Electron spin tracking D. Barber (DESY)

9. Submitted Research Proposal Proposal Title: Advanced Electron Ion Collider Design Program:Research and Development for Next Generation Nuclear Physics Accelerator Facilities(DOE Financial Assistance Funding Opportunity Announcement LAB 10-339) Amount request: $4.5M over 3 years Status:Pending (initial feedback is positive) Project • Collider Ring Design • Numerical Simulation of Beam-Beam and Other Beam Dynamics • Development of a Spin Manipulation and Stabilization System For a Future Electron-Ion Collider • Development of Advanced Electron Cooling Systems

10. Present Research Focal Points We will concentrate R&D efforts on the most critical tasks (proposed Feb. 2010) Focal Point 1: Forming high-intensity short-bunch ion beams & cooling Sub tasks: Complete design of the RF linac and pre-booster Ion bunch dynamics and space charge effects (simulations) Led by Peter Ostroumov (ANL) Focal Point 2: Electron cooling of medium-energy ion beam Sub tasks: Electron cooling dynamics (simulations) Complete design of the ERL-based circulator cooler Dynamics of cooling electron bunch in an ERL circulator ring Focal Point 3: Beam-beam interaction Sub tasks: Include crab crossing and/or space charge Include multiple bunches and interaction points Including space charge effect for low ion energy

11. Path Forward and Strategy • Short term by next EIC AC Meeting ~12/2010 • Complete a conceptual design with sufficient technical details • Plug holes and fill design gaps • Conservative position on accelerator technology design completeness over technology innovation & collider performance • Intermediate term by next NSAC RLP ~2013 • 1st Half • Design optimization (still technology conservative) • Type I R&D: issues which will improve creditability of design and save cost • 2nd Half • Design optimization (modest technology forward looking) • Type II R&D: issues which will improve collider performance and save cost • Long term by ZDR/CDR ~2016 • Design optimization, technology aggressive • Type III R&D: issues for maximum pay-off for best collider performance

12. Open Questions • What are the most important R&D issues? • Given present resources and expertise, how we prioritize these critical R&D topics? • What are the reasonably achievable goals for • Short term R&D, by next EIC AC meeting, Feb. 2011 • Intermediate term R&D, by next NSAC LRP, 2013 • What expertise we should add to the local design team? • What new external collaborations we should seek to establish?